One of the significant problems on mobile devices is the power consumption. Everyone seems to have the experience to drain out the battery of a phone or any other mobile device. Without the support of the electricity, the mobile device becomes useless and all its functionalities stop working. Traditionally, the manufacturers develop large capacity battery in order to provide longer working hours for the mobile device. However, as the screen size of mobile device becomes larger and larger, the power consumption is increased accordingly.
As early as 2008, TPO announced a power saving display sensor. Taiwanese display manufacturer figured out how to integrate ambient light sensors into a standard LCD screen, resulting in more accurate light readings than the usual external sensor setup. The system can also compensate for temperature with the addition of a black level sensor, which means the screen can detect light levels from 3 to 10,000 lux and adjust the backlight accordingly. The sensors were designed for small screens in mobile devices, and the system is estimated to reduce overall power consumption around 30% under normal use.
In 2009, ROHM Semiconductor announced a new family of analog and digital Ambient Light Sensor (ALS) ICs for the efficient control of LED backlighting for LCD-equipped devices. It can save 50% or more of the overall power consumption for operating LCD-equipped devices by adjusting the LED backlight intensity to compensate for varying ambient light levels.
The present invention provides an enhanced method for saving power consumption of display screen regardless of whether it is used by a portable device or not.